Hmm, that's a good question. I too have been trying out all the alternative consoles for Dizzy games to see what's unique about each one.
This list may help you find them all. For the most part it seems as if the Sinclair ZX Spectrum is the primary target of the "8-bit" games, while the Commodore Amiga is the premiere system for the "16-bit" updates. Also the 8-bit versions usually seem more difficult to me, and some of them are actually more sophisticated in my opinion, so that's something to consider when you're deciding which version of an official Dizzy game will give you the best experience.
I know for sure all the ZX Spectrum Dizzy games had ports to the Amstrad CPC and the Commodore 64, and with the exception of Crystal Kingdom Dizzy, all the adventure games had nearly all their graphics copied exactly onto those other computers, so they tend to play pretty similarly. I think the Amstrad CPC versions are the closest in terms of gameplay and music because of some kind of similarities in architecture with the Spectrum; I remember reading that the Oliver Twins actually coded their old Spectrum games on the CPC and transferred the programs over, so it was probably easy enough to just keep that code and only change what was needed for the Amstrad computer to be able to display it. The disadvantage with the CPC is that the high-resolution mode used for the classic Dizzy games only allows four colors, so all the graphics in all those ports had to be reduced to just black, white, red, and green. As if to make up for this, Dizzy's sprite was given a green sheen and red eyes in the early games.
I'm still working my way through the Commodore 64 games, but I'm starting to see what others have said about the physics being a little bit off. I think they made Dizzy's jump a little bit higher, because I was rolling more in the first game, and there's something wrong with the ceiling collisions in the second game where Dizzy gets stuck in place in the ceiling for a while rather than sliding along it. And early games gave Dizzy these creepy squinty eyes. Commodore 64 Dizzy ports are also the most likely to have different music than the rest, but the music tends to sound pretty cool with the Commodore's sound capabilities. Though there was one time when it was the Amstrad CPC that had the different music: In the very first Dizzy game, "The Ultimate Cartoon Adventure", the CPC had a completely different title theme, and was also the only version to have in-game music, but then it only had one sound effect. So that's worth checking out. Finally I should note that,
as this review points out, the "Kwik Snax" on C64 is nothing like Kwik Snax on any other system, so you could consider it its own separate game, possibly even closer to Fast Food!
So those are the reasons I think there's often a slight preference for the Spectrum, at least if you can tolerate that color bleeding effect. The Spectrum Dizzy games also seem to be the most likely to feature both music and sound effects. But does anyone know why the music in Spectrum Dizzy adventure games tends to be a whole step lower in pitch than the same music on any other system?
Now, if you're familiar with all the Amiga games, you should know the Atari ST and IBM-PC versions are VERY much the same. I've even found the same glitches in different versions! Typically the Amiga appears to have the edge with its rather advanced sound generation and greater screen height (at least in PAL)--I noticed some of the Atari ST and PC ports had to reduce the status bar to a thin black strip. In MagicLand Dizzy and Dizzy Prince of the Yolkfolk they even had to take out the scoreboard, which makes it pretty absurd when numbers of points float out of the stars and coins in Prince of the Yolkfolk but don't get stored anywhere.
I mentioned the Amiga usually has the coolest music, but the music on PC often sounds pretty good if you have the right soundcard setup. The PC games can also give you some interesting options like converting the graphics to work on CGA or EGA displays, or deciding what graphic effects and inventory style to use in Fantastic Dizzy. Atari ST can only do music with those old-fashioned square waves, but you might end up liking that sound too. As with Commodore 64, about half the Dizzy games on the ST had whole new soundtracks put in for whatever reason, so it might be worth starting up the games if you can find them, just to listen to the new tunes.
Now, while Fantastic Dizzy was on PC and Amiga, in its case I think the main target for the 16-bit port was the Sega MegaDrive/Genesis, so you'll probably find that version the best--but it wasn't the first version of Fantastic Dizzy made! That game's story starts with The Fantastic Adventures of Dizzy on the Nintendo Entertainment System.
That Treasure Island Dizzy for NES you mentioned? Yes, it was mostly like the Amiga/ST versions. But I like it just for having a graphic style all its own, as well as containing some
unique secrets! If you want to play it, remember it's only available on a compilation cartridge called Quattro Adventure (or Super Adventure Quests in Europe, but Quattro Adventure is probably easier to find). Quattro Adventure contained a few other hard-as-nails platform games you might enjoy, including the original version of Robin Hood: Legend Quest and the first Linus Spacehead game, which had a more famous sequel, Linus Spacehead's Cosmic Crusade or simply Cosmic Spacehead.
Quattro Arcade was another NES four-in-one compilation that contained another Dizzy game, Go Dizzy Go, which was essentially a sequel to Kwik Snax. Although, since all the Dizzy arcade games had completely different layouts in 16-bit compared to 8-bit, I tend to think of the Amiga/ST/PC versions of Kwik Snax as Kwik Snax 2 and Go Dizzy Go as Kwik Snax 3. Quattro Arcade also included the NES version of C.J.'s Elephant Antics if you were interested in that game.
So then, The Fantastic Adventures of Dizzy was the first really new Dizzy adventure for Nintendo. But watch out when you hunt down a copy, because there were
three different versions of the game on the NES alone, and the first two versions were VERY different. The later versions are the ones that all the ports to other systems were based on, so the first version ("blue version" as it's often called due to the different title color) is the most unique, but it's also the most frustrating. It's up to you if you also want to play the "red versions" for NES, but the Sega Master System and Game Gear ports were based so closely on the final NES version that you might as well just play one of the Sega versions to see what their additional changes were. Thus in Fantastic Dizzy's case, NES, SMS, and GG were the "8-bit versions", and Genesis, Amiga, and PC were the "16-bit versions", and there wasn't any Fantastic Dizzy on 8-bit computers unless you count the two mini-games that were turned into stand-alone action games, Bubble Dizzy and Dizzy Down the Rapids.
Dizzy the Adventurer was notable for being the game released with the short-lived Aladdin Deck Enhancer when it first came out, but if you're playing on emulators you won't need to worry about the cartridge format. The game itself is an update of Dizzy Prince of the Yolkfolk, building on the way it was already updated for the 16-bit computers. It's been praised for adding more character interactions that can give hints to new players and make the game's world feel livelier, similar to how Crystal Kingdom Dizzy was updated for 16-bit computers. Additionally a few puzzles have been added and some re-arranged so generally there's more adventuring and less backtracking if you know what you're doing. I think this was also the game where Dizzy gained his ability to run faster. Too bad it was also one of his last. It's also a shame the NES version made the music sound so scratchy, which I guess is one point in the SMS version's favor. The SMS version also made the game a bit harder by turning the torches lethal again and adding new enemies like bees and cave drips, although I sometimes wish they put the life bar back in if they were going to do that. Also the ending of Prince of the Yolkfolk/Adventurer seems to get less interesting with every new version they make, sheesh.
So then if you're looking up Sega Master System/Game Gear Dizzy games, remember that while Fantastic Dizzy was stand-alone, three others were only contained in a compilation called The Excellent Dizzy Collection. Dizzy the Adventurer and Go Dizzy Go were pretty straight ports of the NES games, but Go Dizzy Go and Fantastic Dizzy got whole new soundtracks once again. The music in the Sega version of Go Dizzy Go seemed inspired by the original Kwik Snax on Spectrum, while the Nintendo version sounded more like polka I think. And then Panic Dizzy is very important to note, because like Kwik Snax on Commodore 64, the Panic Dizzy on The Excellent Dizzy Collection is nothing like any other version of Panic Dizzy (or Dizzy Panic). Instead of dropping shapes through the right holes, you're arranging stacks of blocks by pulling them off the ceiling and throwing them back on. You might enjoy it, I don't know.
One thing I would recommend is to play the NES games, and possibly all the video game console games, in NTSC (60 Hz) mode, because they seem to have been designed with that speed in mind, possibly for American distribution first. The home computer games you should probably at PAL (50 Hz) speed, unless you find it too boring and don't mind the music being too fast. Later CodeMasters console games would actually detect what kind of system they were played on and speed up the music and such on PAL to match the NTSC speed better, so that's one reason I feel they were aiming for NTSC first with those.
Finally, I know a lot of the old computers had their own compilations of games which had already been released stand-alone. I haven't done much research into them, but typically they don't change anything. Only possible changes I can think of right now are when someone on another topic said an error in the Commodore 64 version of Dizzy The Ultimate Cartoon Adventure was fixed in some collection, and when I noted all the changes I could spot in The Big 6 in the longplays topic, which were mostly unimportant except for Fantastic Dizzy and possibly Crystal Kingdom Dizzy.